Coolant Heat Exchanger Having A Scraper For Each Heat Exchange Interface Surface

ABSTRACT

The heat exchanger is adapted for cooling a coolant (e.g., water), used to cool a device or an area (e.g., building interior), such as during periods of peak energy cost and usage, to save energy and energy costs. The heat exchanger includes a coolant storage tank with one or more refrigerant circulators in contact with the floor of the tank. The circulators use a refrigerant having a freezing temperature colder than the coolant, with coolant on the floor of the tank forming a layer of ice thereon. A rotary scraper extends up through the tank floor from each circulator, with the scrapers operating to remove the thin layer of ice from the floor as the ice forms. The resulting ice chips are relatively small and thin, thus having a relatively large surface area for their volume in order to maximize melting and rapid cooling of the coolant.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to heating and cooling systems,and particularly to a heat exchanger in cooling systems to save energyin cooling operations, such as during peak utility use periods.

2. Description of the Related Art

The need to produce heated or cooled air or other fluid, and/or totransfer warmer or cooler air or other fluid from one location toanother, has been evident for some time. Contemporary means for coolingthe interior of a structure is by air conditioning, essentiallycomprising a fluid refrigerant that changes phase from liquid to gasdepending upon its temperature and pressure. A compressor is used todrive the refrigerant through the system, with expansion of the fluidfrom liquid to gas resulting in a decrease in temperature that istransferred to the area being cooled. More generally, such systems areknown as “heat pumps,” and are reversible to deliver warmer air into thestructure when desired.

All of these systems require energy input, as their compressors aregenerally relatively high power demand devices. They are generallypowered by electrical power from the local electrical grid or network.Electrical power companies have long recognized that electrical demandis greatest at certain times of the day, depending upon the season andambient temperature. In warmer conditions, electrical demand is ofcourse highest during the warmest part of the day, with demanddecreasing as the temperature cools. Accordingly, electrical powercompanies generally increase the cost of electricity to the consumerduring the periods of greatest demand, both to encourage conservativeuse during those periods in order to encourage reducing the need formore power production, for example.

A number of devices have been developed in response to theabove-described electrical rate adjustment system, with such devicesuniversally operating during off-peak times and storing the resultingcold mass (e.g., water, etc.) to cool the desired area during periods ofhigher energy cost, typically during the warmer part of the day. Thesedevices generally operate at a sufficiently low temperature as toproduce ice buildup on the water contact surface of the interfacebetween the cooling agent and the water being cooled. Ice production isdesirable, as the colder temperature of the ice is capable of absorbingmore heat from the volume being cooled. However, it can be difficult toremove ice from the freezing surface (e.g., cooling coils, etc.), whichice removal process requires energy over and above the energy requiredfor cooling. Also, many such systems produce ice in relatively largevolumetric units (e.g., ice cubes or blocks, etc.), with the relativelyhigh volume to surface area ratio of such ice reducing the ability ofthe ice to melt rapidly to absorb heat from the water.

An example of a device to remove ice from a surface is found in JapanesePatent Publication No. 3-204577 published on Sep. 16, 1991 to DaikinIndustries, Ltd. This reference describes a hollow cylindrical containeradapted to form ice upon its inner surface. A concentric shaft rotateswithin the cylinder, with elongate scraper blades extending radiallyfrom the shaft to bear against the inner wall of the cylinder. Theblades are stiffened by a metal insert to limit distortion.

An example of a cooling system that produces water ice for use incooling the water in the system is found in Japanese Patent No.2000-304307 published on Nov. 2, 2000 to Tohoku Electric Power Co. etal. This reference describes a cooling system having several tanks, withice being formed in one tank and then transferred to another tank formelting and cooling water within that tank.

Thus, a heat exchanger addressing the aforementioned problems isdesired.

SUMMARY OF THE INVENTION

Embodiments of a heat exchanger essentially include a coolant tank orcontainer having a coolant inlet manifold at its top and a coolantoutlet manifold at its bottom. The coolant is preferably water, but maybe some other liquid as desired. The tank includes a series ofperforated baffles therein to limit the movement of ice within the tankwhile still allowing water to flow through the perforations of thebaffles, thus providing a greater amount of water flow and contact withthe ice within the tank.

At least one, and desirably a series of, refrigerant circulators areinstalled adjacent the floor of the tank. Each of these refrigerantcirculators desirably has a low, flat circular form with a coil orspiral coolant path therein. Inlet and outlet manifolds are provided totransfer refrigerant to and from the circulators. The refrigerant can bea brine solution to produce a freezing point lower than that of purewater, or the refrigerant can be some other solution having a relativelylow freezing point, such as having a freezing point lower than thecoolant, for example.

As the refrigerant circulators are in contact with the floor of thetank, ice forms from the coolant, such as water, on the floor of thetank during operation of the system. Accordingly, each of thecirculators has a rotary scraper extending upwardly therefrom, the shaftof the rotary scraper extending through the floor of the water tank. Thescrapers rotate, such as over the floor of the tank, to remove the iceformed from the cooled coolant on the floor from the bottom of the tank,with the removed ice having the form of a multitude of very thin iceflakes to maximize the surface area of each piece of ice and thereforemaximize heat transfer from the water to melt the ice. The coolant, suchas the chilled water (or other coolant), can be stored in the tank untilneeded, or the coolant can be circulated from the coolant inlet manifoldthrough the tank to the coolant outlet manifold, and then removed fromthe tank through the coolant outlet manifold for use in coolingoperations, such as in another area (e.g., the interior of a buildingstructure, etc.) or device, for example.

These and other features of the present invention will become readilyapparent upon further review of the following specification anddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a heat exchanger according to thepresent invention, illustrating its basic structure.

FIG. 2 is a side elevation view in section of the heat exchangeraccording to the present invention, illustrating further detailsthereof.

FIG. 3 is a detailed perspective view of a refrigerant circulator of theheat exchanger according to the present invention, illustrating detailsthereof.

FIG. 4 is a top perspective view of an array of refrigerant circulatorsof the heat exchanger according to the present invention.

FIG. 5 is a bottom perspective view of the array of refrigerantcirculators of FIG. 4, of the heat exchanger according to the presentinvention.

FIG. 6 is a top perspective view of the coolant inlet manifold of theheat exchanger according to the present invention, illustrating detailsthereof.

FIG. 7 is a top perspective view of the coolant outlet manifold of theheat exchanger according to the present invention, illustrating detailsthereof.

Unless otherwise indicated, similar reference characters denotecorresponding features consistently throughout the attached drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The heat exchanger uses a refrigerant that is cooled, such as can besuitably cooled during off-peak periods of electrical use when the costof electrical power, or other energy, such as natural gas, can be lessexpensive, for example, and the refrigerant is used to cool a liquidcoolant, such as water or other suitable coolant liquid. The water orother coolant can then be used to cool a location, an area (e.g.,building interior, etc.), a structure or a device, for example, to saveenergy during a cooling operation.

FIG. 1 of the drawings provides a perspective view of an embodiment of aheat exchanger 10, with FIG. 2 providing an elevation view of the heatexchanger 10 in section. The heat exchanger 10 includes a coolant tank12 for water or other coolant, as desired. The coolant tank 12 is asubstantially closed structure having a floor 14, side walls 16, and atop 18, with the floor 14, the walls 16, and the top 18 defining aninterior volume 20 of the coolant tank 12. The interior volume 20includes a plurality of vertically oriented, perforated baffles 22therein, with the baffles 22 serving to reduce movement of ice withinthe coolant tank 12, while the perforations 24 (shown more clearly inFIG. 2) allow a relatively free flow of water (or other coolant) in theinterior volume 20, for example. The heat exchanger 10 can be supported,such as in a generally upright position, on a suitable supportingarrangement, such as a platform and column type supporting structure 11illustrated in FIGS. 1 and 2, for example.

A plurality of refrigerant circulators 26 are installed adjacent thefloor 14 of the coolant tank 12, and serve to circulate a suitablerefrigerant in contact with or in communication with the tank floor 14in order to cool the coolant within the coolant tank 12. While a singlerelatively large refrigerant circulator 26 can be provided, it isdesirable to provide a relatively large number of refrigerantcirculators 26, e.g., nine in a three by three matrix as shown in FIGS.4 and 5 for the substantially square platform of the tank floor 14 inthe illustrated embodiment of the heat exchanger 10, and the number ofrefrigerant circulators used can depend on the particular use orapplication, for example.

FIG. 3 illustrates a single exemplary refrigerant circulator 26. Therefrigerant circulator 26 has a suitable configuration for a use orapplication, such as a generally circular configuration, and includes arefrigerant pathway 28, such as a closed spiral refrigerant pathway,provided for the refrigerant to flow therethrough. The refrigerantpathway 28 is defined by a spiral wall 30 that is positioned between abottom 32 of the refrigerant circulator 26 and the adjacent, overlyingfloor 14 of the coolant tank 12. A circular portion of the floor 14 isshown covering the spiral wall 30 and closed spiral pathway 28 of therefrigerant circulator 26 in FIG. 3, with it being understood that thefloor portion 14 shown in FIG. 3 is a relatively small portion of thefloor 14 of the coolant tank 12 in FIGS. 1 and 2. Thus, the refrigerantcirculating within the refrigerant circulator 26 is in contact with thelower surface of the floor 14, to remove heat conducted through thefloor 14 from the overlying coolant within the interior volume 20 of thecoolant tank 12 to cool the coolant.

The refrigerant used in the refrigerant circulators 26 of embodiments ofa heat exchanger, such as the heat exchanger 10, is typically desirablya liquid having a freezing point lower than that of the coolant in thecoolant tank 12, such as pure water as the coolant. With water as thecoolant, a brine solution is desirably used as the refrigerant, due toits low cost and relatively low freezing point, for example. Althoughthe refrigerant is typically in a liquid state when cooled below thefreezing point of the coolant, such as water as the coolant, the heattransfer from the coolant, such as water or other coolant, within thecoolant tank 12 through the floor 14 to the refrigerant within therefrigerant circulator 26 results in a relatively thin sheet of iceforming on the upper surface of the floor 14 from the cooling of thecoolant. If this formed ice is allowed to build up, it typicallythickens and can then act as an insulator between the subfreezing floor14 and refrigerant therebelow and the remaining liquid coolant, such aswater, within the coolant tank 12. It is desirable that this ice beremoved and allowed to float upward in the coolant tank 12, to moreeffectively cool the water within the coolant tank 12, such as toenhance saving energy in a cooling operation of the heat exchanger 10.

Accordingly, an ice scraper mechanism or an ice scraper device 35, suchas including a rotary scraper shaft 34 communicating with a hub 38 towhich one or more ice scraper blades 36 are attached, can desirably beprovided for each of the refrigerant circulators 26. The ice scrapermechanism or ice scraper device 35 can be integrated with, incommunication with, or separate from the one or more refrigerantcirculators 26, such as depending upon the use or application, forexample. Also, a single ice scraper mechanism or ice scraper device 35,or a plurality of ice scraper mechanisms or ice scraper devices 35, canbe provided for ice removal for ice formed over the floor 14 of thecoolant tank 12 from the cooling of the coolant, such as depending onthe use or application, for example. The ice scraper mechanism or icescraper device 35 is desirably arranged and positioned adjacent to thecorresponding refrigerant circulator 26, and the one or more ice scraperblades 36 are positioned over the floor 14 of the coolant tank 12 andcan be desirably positioned in opposing relation to a correspondingrefrigerant circulator 26, for example. The rotary scraper shaft 34 (theupper end of which may be seen in FIG. 3) is generally concentric withthe refrigerant circulator 26, and extends upwardly therefrom to passthrough the floor 14, such as normal or substantially normal to theplane of the floor 14, for example.

At least one ice scraper blade 36 extends radially from the hub 38 atthe upper end of the rotary scraper shaft 34, there desirably being twoor more such ice scraper blades 36; and three ice scraper blades 36 areillustrated in the ice scraper mechanism or the ice scraper device 35 inFIG. 3, for example. A motor, or other suitable motive device, can beprovided beneath or associated with the refrigerant circulator 26, suchas in the hub 38, or communicating with the rotary scraper shaft 34, orlocated at some other suitable location, to rotate the ice scraperblades 36. The motor, or other suitable motive device, can beconventional, e.g., electric, or perhaps hydraulic, depending upon theflow of refrigerant through the refrigerant circulator 26, to rotate theshaft 34, the hub 38, and the attached one or more ice scraper blades36, for example.

Each ice scraper blade 36 has a leading edge 40 that is positioned overthe floor 14, such as in contact or substantial contact with the uppersurface of the floor 14, i.e., the surface of the floor 14 incommunication with the interior volume 20 of the coolant tank 12. As theice scraper blades 36 move, such as rotate, their leading edges 40 bearagainst or move over the underlying surface of the floor 14 to scrapeand remove ice formed from the cooling of the coolant in the coolanttank 12 that can form on the upper surface of the floor 14 within thecoolant tank 12. Desirably, only a relatively thin sheet of ice isallowed to form before the ice scraper blades 36 remove the ice. Theremoved ice is thus in the form of a relatively small and very thinsheet or crust having a relatively large surface area for its volume.This results in the chips of ice melting relatively rapidly, i.e.,absorbing the heat from the surrounding water as they float upwardwithin the coolant tank 12. This can result in relatively highefficiency in cooling the coolant, such as water, within the coolanttank 12.

Each refrigerant circulator 26 includes a first or inlet opening 42adjacent the periphery of the refrigerant circulator 26 and a second oroutlet opening 44 generally positioned adjacent the center of therefrigerant circulator 26. In this configuration, the brine (or otherrefrigerant) flows into the peripheral inlet opening 42 and flows byspiraling inwardly, for example, along the refrigerant flow path 28 andout of the refrigerant circulator 26 via the central outlet 44. However,it will be seen that the flow direction may be readily reversed, if sodesired, depending upon the particular use or application, for example.

It is further desirable that a plurality of refrigerant circulators 26be provided, e.g., nine in a three by three matrix, as shown in FIGS. 1,2, 4 and 5, although the amount, arrangement and type of refrigerantcirculators 26 can vary depending upon the use or application, forexample, and should not be construed in a limiting sense. As illustratedin FIGS. 4 and 5, for example, a first refrigerant inlet manifold 46having a series of branches 46 a connects to the peripheral inletopenings 42 of the refrigerant circulators 26, as shown in the bottomperspective view of FIG. 5, with a second refrigerant outlet manifold 48having a series of branches 48 a connecting to the central outlets oroutlet openings 44. The first refrigerant manifold 46 receives chilledrefrigerant (brine, etc.), such as from a conventional source ofrefrigeration. Refrigerant that has absorbed heat from the coolant, suchas water (or other liquid coolant), in the coolant tank 12 is returnedvia the second refrigerant outlet manifold 48 to be cooled again, suchas until the cooling cycle is terminated.

Coolant flow (water, etc.) is provided through the coolant tank 12 in asimilar manner, as shown in FIGS. 1 and 2. A first coolant manifold 50having a coolant inlet 51 and having inlet manifold branches 50 a isinstalled in the upper portion of the coolant tank 12, and a secondcoolant manifold 52 having outlet manifold branches 52 a and having acoolant outlet 53 is installed, such as in opposing relation to thefirst coolant manifold 50, in the lower portion of the coolant tank 12generally just above the ice scraper blades 36. The ends of the inletmanifold branches 50 a and the outlet manifold branches 52 a aresupported by internal crossmembers 54 within the coolant tank 12, asshown in FIG. 2, for example.

Desirably, the upper or first coolant manifold 50 is typically used asan inlet for the coolant, the coolant entering the first coolantmanifold through the coolant inlet 51, with FIG. 6 providing a detailedview of the first coolant manifold 50. It is also desired that thecoolant tank 12 not be completely filled with the coolant, but thatthere be some space at the top of the coolant tank 12 near the upperends of the baffles 22. Accordingly, the inlet manifold branches 50 a ofthe upper first coolant manifold 50 are provided with a large number ofsmall spray passages or orifices 56 to spray the coolant, such as water(or other coolant), into the interior volume 20 of the coolant tank 12.Depending upon the humidity within the coolant tank 12, this can havesome additional cooling effect due to evaporation in the upper portionof the coolant tank 12, for example.

The lower second coolant manifold 52 is typically used as an outletmanifold for the coolant, the coolant exiting from the second coolantmanifold 52 through the coolant outlet 53. The outlet manifold branches52 a of the second coolant manifold 52 include a number of upperpassages, such as the upper passages 55 a, 55 b and 55 c, disposed alongeach of the branches 52 a, as illustrated in FIG. 1 and FIG. 7. Thespecific configuration of these upper passages, such as the upperpassages 55 a, 55 b and 55 c, can be of various configurations, such asdependent upon the particular use or application, so long as the upperpassages, such as the upper passages 55 a, 55 b, and 55 c, can receivethe coolant and can permit or facilitate the flow of the cooled coolant,such as water (or other coolant), from the coolant tank 12, such as to alocation, an area (e.g., building interior, etc.), a structure or adevice, requiring cooling, for example.

Where separate passages or ports are provided, such as the upperpassages 55 a, 55 b and 55 c, the more distal ports are desirablysomewhat larger in diameter than the ports or passages relatively closerto the second coolant manifold 52, in order to assist in relatively moreevenly distributing flow of the coolant from the coolant tank 12, forexample. In this regard, as illustrated in FIG. 7, the upper passage 55a has a diameter D1 that is larger than a diameter D2 of the upperpassage 55 b, and the upper passage 55 b has the diameter D2 that islarger than a diameter D3 of the upper passage 55 c, for example.

Accordingly, embodiments of a heat exchanger, such as the heat exchanger10, can provide a relatively efficient means of cooling a location, anarea (e.g., building interior, etc.), a structure or a device, as wellas can enhancing energy saving in the cooling process or operation.Also, embodiments of a heat exchanger can also operate to remove heatfrom an area or volume at some selected time according to the desires ofthe user, such as to take advantage of lower rates for electrical power.Further, embodiments of a heat exchanger in cooling a coolant canpotentially decrease the operation of relatively high energy demanddevices, such as compressors and the like, during periods of higherenergy costs, for example. The embodiments of the heat exchanger thuscan provide a potential savings for the operator or user thereof.

It is to be understood that the present invention is not limited to theembodiments described above, but encompasses any and all embodimentswithin the scope of the following claims.

1. A heat exchanger, comprising: a coolant tank to receive a coolant,the coolant tank, defining a closed structure, having a floor and aninterior volume; *a plurality of refrigerant circulators, each of theplurality of refrigerant circulators including the refrigerant path andhaving a first inlet opening adjacent the periphery to receive arefrigerant to cool the coolant and a second outlet opening adjacent thecenter thereof to flow the refrigerant out from the refrigerant path; aplurality of perforated baffles disposed vertically within the interiorvolume of the coolant tank; and at least one ice scraper device toremove ice formed over the floor of the coolant tank from cooling of thecoolant by the at least one refrigerant circulator, the at least one icescraper device including at least one ice scraper blade, the at leastone ice scraper blade positioned over the floor of the coolant tank, theat least one ice scraper blade selectively moving over the floor toscrape and remove the ice formed over the floor of the coolant tank. 2.The heat exchanger according to claim 1, wherein each one of theplurality of refrigerant circulators has a periphery and a center and arefrigerant path therein.
 3. The heat exchanger according to claim 2,further comprising: a first refrigerant manifold communicating with eachof the first inlet openings; and a second refrigerant manifoldcommunicating with each of the second outlet openings.
 4. The heatexchanger according to claim 1, further comprising: a coolant inletmanifold communicating with the interior volume of the coolant tank toflow the coolant into the coolant tank; and a coolant outlet manifoldcommunicating with the interior volume of the coolant tank to flow thecoolant from the coolant tank.
 5. The heat exchanger according to claim4, wherein the coolant inlet manifold includes a plurality of inletmanifold branches, the plurality of inlet manifold branches including aplurality of spray passages therein to spray the coolant into theinterior volume of the coolant tank, and the coolant outlet manifoldincludes a plurality of outlet manifold branches, the plurality ofoutlet manifold branches including a plurality of passages of differentdiameters to receive the coolant to distribute the flow of the coolantfrom the coolant tank.
 6. (canceled)
 7. The heat exchanger according toclaim 1, wherein the refrigerant comprises a brine refrigerant tocirculate through the at least one refrigerant circulator. 8-20.(canceled)